The species of cardinalfishes commonly available to the hobby are tight schooling species, which makes a nice and peaceful addition to any reef aquarium big enough to keep a school. Not all cardinalfishes are schooling species, and most are also nocturnal. Cardinals are one of a few marine fish families in which oral brooding of eggs occur. In the case of the Banggai Cardinal (Pterapogon kauderni), the larvae remain in the oral cavity of the male for an additional 10 days until completion of the development and leave the mouth as juveniles. Some species that fall in the genus of Apogon have recently been elevated to full generic rank. Most of the Indo-Pacific species that were formerly classified in Apogon are now in Ostorhinchus, such as the Redspots Cardinal (Ostorhinchus parvulus), and the Threadfin Cardinal now classified as Zoramia leptacantha.
